CK2 won't launch/start at all [fixed!]

[sblahful]

TL;DR: Windows Defender Real Time Protection was the problem for me. See (5) for full details of how to fix.


Hi folks,
I've had this problem recently and wanted to share the solution in case it's useful to anyone in future. I've also added all the other 'solutions' I came across and tried in case they work for other people.


Problem:
Recently the CK2 launcher won't load at all. Steam will say 'launching', but then nothing will happen and there's no error message either, which makes troubleshooting pretty hopeless. Weirdly the problem is intermittent - sometimes I'd have no problem at all launching.


Attempted Solutions:

1) Paradox's two suggestions.
https://support.paradoxplaza.com/hc/en-us/articles/203086498-The-game-refuses-to-start
(a) Check for d3dx9_41.dll and d3dx9_43.dll in your C:\windows\system32\ directory. If missing, reinstall from http://www.microsoft.com/download/en/details.aspx?id=35
(b) Right click c:\program files (x86)\steam\steamapps\common\crusader kings 2\ck2game.exe. Set compatibility to run in 640 X 480. Launch game and change resolution in game.


2) Reinstall C++ support files (Can't remember where I saw this, but apparently EU4 & CK2 can have problems with C++.)
In steamapps\common\Crusader Kings II\_CommonRedist there's a few files you can re-run:
(a) \DirectX\Jun2010\DXSETUP.exe (b) vcredist\2010\vcredist_x64.exe (c) vcredist\2010\vcredist_x86.exe


3) Appaul's Youtube general Steam game fixes
https://youtu.be/O0TyTZoaFhA // https://appuals.com/fix-steam-game-wont-launch-windows-10/
(a) Right click steamapps/common/crusader kings 2/ck2game.exe. Set compatibility to run in compatibility mode for Windows 8.
(b) In Task Manager, end Steam Client Bootstrapper to fully close Steam. In c:\program files(86x)\steam, rename ClientRegistry.blob to ClientRegistryold.blob


4) Steam's generic Suggestion
In Steam, right-click on the game name. Open Properties. Under the Local Data tab, click 'Verify local files'. Be patient.


5) u/Th0rium's solution: [THIS WORKED FOR ME]
https://steamcommunity.com/app/203770/discussions/0/1694917906659413667/
Go into Windows Defender Security Center -> Virus & Threat Protection -> Virus & Threat Protection settings and there click on "Allow an app through controlled folder access". You find this under the Headline "Controlled folder access". And there add you the CK2game.exe


Honestly, I was pretty underwhelmed by Paradox's support suggestions to be honest and thought it'd be useful to have a bunch of solutions people can try out in one place instead of hunting through different ancient support links. If you're reading this in 2025, I hope this helps!

xkcd.com/979/

[Varainger]

Originally posted by sblahful:

Honestly, I was pretty underwhelmed by Paradox's support suggestions

Who you neither talked to nor contacted in any way.
Reading old FAQs is rarely working and is realy not the same.
Just saying this ,as you implied it.

To do so , registration is required and that's not that user friendly and slightly annoying,
The registering process is not very upfront and that's when i'd agree.

By the way, the fix you mentioned is pretty old and only one of many issues and appropriate fixes, where the symptoms might be the same or similar. Same as in medicine.
Tech support usually suggests this as one of several standard options, if the inital post isn't clear about the issue or they are unsure about the cause.,

I don't say this to be condescending or an arse or anything, but because i do unasked for voluntary tech support here (so to be clear i'm just another forum user) and know about it. Apart form that it's of course nice that you posted what you found and shared your knowledge, which i like and appreciate.
Cheers

PS: I still hope for and expect a final (or two/three) bug fixing patches, after which the issues with the game might hopefully be not so many, especially the annoying Win10 protection issues..
One can dream.

[ftstargino]

In Friday I buy Rajas of India and Monks. After that my crusaders 2 dont play.

[Judas]

tried all this and nothing works Neither EU4 or CK2 will launch but city skylines and stellaris will. There are the only 2 games in my library that wont launch

[sblahful]

Originally posted by Varainger:

Originally posted by sblahful:

Honestly, I was pretty underwhelmed by Paradox's support suggestions

Who you neither talked to nor contacted in any way.
Reading old FAQs is rarely working and is realy not the same.

If I'd not been able to fix it, I certainly would have contacted them directly, but IMO contacting support should really be a last resort.

All I was trying to convey was that it would be helpful if Paradox could have a more comprehensive troubleshooting resource on their website. Posting this is my own way of trying to fill that gap.

In any case, hats off to you for doing your bit to help players.

[sblahful]

Originally posted by pmumberson:

tried all this and nothing works Neither EU4 or CK2 will launch but city skylines and stellaris will. There are the only 2 games in my library that wont launch

Yeah I found EU4 would launch when CK2 wouldn't - have you tried turning off your antivirus/windows defender completely?

If you're using windows, load Event Viewer (every windows edition has it I believe) and check Windows Logs -> Application. An error log may appear when you try to load your game. Searching for the error code online might lead you to a solution.

[Varainger]

Originally posted by sblahful:

If I'd not been able to fix it, I certainly would have contacted them directly, but IMO contacting support should really be a last resort.

All I was trying to convey was that it would be helpful if Paradox could have a more comprehensive troubleshooting resource on their website. Posting this is my own way of trying to fill that gap.
.....

I understand that...normally, but Paradox games are, not only CK2,...errr.....let's say 'challenging', also regarding the tech side, getting them to actually launch.

"More comprehensive troubleshooting resource", sounds nice, but it might just confuse a lot of people and believe me it would likely be phrased in a non-practical way that many can't follow and understand and too long. Who reads a tech bible, when a tech support issue needs fixing right now ?! See my point. Not to mention again the similar symptoms , doesn't mean the same fix will work, different issues appear with different patches etc.

It's also too often a good excuse for the managment to cut resources on human tech support, even if the non-human information isn't helping. Their (human) tech support is quite good and open, as long as people actually respond on their questions and provide good and clear info to work with, which is often enough not the case. It's better than a 'comprehensive list' could be. The customers' side communication is often rather lacking in that regard ( again, i follow that since CK2 got released and understand now why working in tech support isn't necessarily a dream job, especialythe repetitive comunication challenges), but again i know what you mean and think it could improve here and there, but i follow that for years and don't expect Paradox to change or have tech suport easier accessible than most other game developers.
Then they have unasked for volunteering people/fools like me, so they don't have to..

Anyway, not the worst of issues on the planet, so...
let me post my simplified current comprehensive list (not for past patches) then ... ;)

quote :

my general list
----------------------------------------------------------------------------------------
Requirement :
- Start the game without mods (uncheck them in the laucher)

Several seperate recent options for launch and crash issues :
(no order/priority, except that a clean reinstall often works)


- Verify integrity of game files (cache) in the games' Steam properties

- restart your computer

- Go into Documents/Para../CK2 and delete the settings.txt file
(gets recreated on start)

- Install Visual c++ 2015. Better a most recent 2015-2019 version.

- be sure you installed DirectX9 and Visual c++2010 and 2015 (x64 and x86)
and that a recent Windows update hasn't crunched them, in which case a reinstall of those is needed.

- move your save files out of the save files folder in Documents/Paradox Interactive/CK2.
Try to open the launcher. If you get asked to allow access to Documents, say yes.
IF the game starts and works fine you can move your save files back again.
That appears to be an issue especialy in ironman and bronzeman saves files getting corrupted and for whatever reason stopping the game from starting.

- Turn off antivirus

- add ck2 as an "app allowed through"/exception in your security/AV

- Check "Disable fullscreen optimisation" in ck2game.exe (right click)
-> Properties -> Compatibility

- edit settings.txt in Documents/Para../CK2 to start in the opposite window mode (yes/no) than what it's set at (fullscreen, borderless; windowed is "no" for both.).

- Disable MSI Afterburner, RivaTuner, RadeonPro, or a gaming VPN app called Evolve,
or the MSI Gaming App, or Duet,

- Rename/Delete the CK2 folder in Documents/Para../ (copy mods and save files accordingly)

- Clean reinstallation:
Manually (!) delete or rename both CK2 folders (in Documents and Steamapps)
and reinstall.

- if there were driver updates, revert them and see if that fixes it.
Especially Nvidia driver updates seem suspect recently.


If there are questions on single points, go ahead and ask.

Last option:
Contact Paradox support via Forum or ticket directly.
See the pinned thread for the two tech support links.

/quote.